Of course, external RAM is an option. However, using external SDRAM increases the complexity of the hardware significantly, which takes away a bit of the elegan

Of course, external RAM is an option. However, using external SDRAM increases the complexity of the hardware significantly, which takes away a bit of the elegance and simplicity of Wirth's original RISC5 FPGA system. Wirth's system used a Xilinx Spartan 3 board with 1 MB of 32 bit wide fast asynchronous SRAM (https://multicores.org/blog/small-is-beautiful.html https://multicores.org/blog/small-is-beautiful.html). Unfortunately, FPGA boards with 32 bit wide SRAM are really hard to find nowadays, especially those supported by SymbiFlow...